25 March 2014  Air pollution – both indoor and outdoor – killed some 7 million people across the globe in 2012, making it the world’s largest single environmental health risk, according to new figures released today by the UN World Health Organization (WHO).

“The risks from air pollution are now far greater than previously thought or understood, particularly for heart disease and strokes,” said Maria Neira, Director of WHO’s Department for Public Health, Environmental and Social Determinants of Health.

“Few risks have a greater impact on global health today than air pollution; the evidence signals the need for concerted action to clean up the air we all breathe,” Dr. Neira added.

In particular, the new data, which cites air pollution as the cause of one in eight global deaths, reveals a stronger link between both indoor and outdoor air pollution exposure and cardiovascular diseases such as strokes and ischaemic heart disease, as well as between air pollution and cancer. This is in addition to pollution’s role in the development of respiratory diseases, including acute respiratory infections and chronic obstructive pulmonary diseases.

“Cleaning up the air we breathe prevents noncommunicable diseases as well as reduces disease risks among women and vulnerable groups, including children and the elderly,” Flavia Bustreo, WHO Assistant Director-General Family, Women and Children’s Health said. “Poor women and children pay a heavy price from indoor air pollution since they spend more time at home breathing in smoke and soot from leaky coal and wood cook stoves.”

Analysing the risk factors, taking into account revisions in methodology, WHO estimates indoor air pollution was linked to 4.3 million deaths in 2012 in households cooking over coal, wood and biomass stoves. The new estimate is explained by better information about pollution exposures among the estimated 2.9 billion people living in homes using wood, coal or dung as their primary cooking fuel, as well as evidence about air pollution's role in the development of cardiovascular and respiratory diseases and cancers.

In the case of outdoor air pollution, the agency estimates there were 3.7 million deaths in 2012 from urban and rural sources worldwide. The most air pollution-related deaths occurred in Southeast Asia and the Western Pacific, according to WHO, with a total of 3.3 million deaths linked to indoor air pollution and some 2.6 million related to outdoor pollution.

Many people are exposed to both indoor and outdoor air pollution. Due to this overlap, mortality attributed to the two sources cannot simply be added together, hence the total estimate of around 7 million deaths in 2012.

“Excessive air pollution is often a by-product of unsustainable policies in sectors such as transport, energy, waste management and industry. In most cases, healthier strategies will also be more economical in the long term due to health-care cost savings as well as climate gains,” Carlos Dora, WHO Coordinator for Public Health, Environmental and Social Determinants of Health said.

“WHO and health sectors have a unique role in translating scientific evidence on air pollution into policies that can deliver impact and improvements that will save lives,” Dr. Dora added.

The release of today’s data is a step in the development of a WHO roadmap for preventing diseases related to air pollution. This involves the development of a WHO-hosted global platform on air quality and health to generate better data on air pollution-related diseases and strengthened support to countries and cities through guidance, information and evidence about health gains from key interventions.